We will recruit a large population of HIV infected individuals in various stages of disease by contacting physicians, appropriate medical, public health and community organizations. All have already given written agreement to encourage patients to participate in the project. Consent will be obtained for enrollment and the collection of clinical and laboratory data. Confidentiality will be assured by a system of coding. We will then perform initial medical examinations and obtain routine laboratory data on all patients participating in the project. Specimens for immunologic and virologic assessment and banking will be collected and separated in the General Clinical Research Center (GCRC). This data and that obtained in scheduled follow- up visits will be entered into the GCRC's CLINFO database in sequential fashion over the entire duration of the study. This database will define the natural history of HIV infection in our population. Based on the initial clinical and laboratory studies, patients and specimens will be triaged to specific protocols (Projects 2, 3 and 5) which will evaluate therapeutic interventions of HIV infection or study basic questions concerning the pathogenesis of AIDS. Patients will have rapid access to state-of- the-art medical care. When they develop opportunistic infections, they will be enrolled in therapeutic protocols, if available, or treated with standard therapy. All information will be included in the database.